/**
 * @fileOverview 补间动画方式扩展工具
 * 
 * @version qinglan_animate 1.0
 * @static
 * @author wxq wxqqh@qq.com
 * 
 * @see http://www.cnblogs.com/cloudgamer/archive/2009/01/06/Tween.html author
 *      cloudgamer
 */
/**
 * 命名空间
 * 
 * @namespace
 * @type Object
 */
window.qinglan = window.qinglan || {};
/**
 * 补间动画命名空间
 * 
 * @namespace
 * @type Object
 */
qinglan.Tween = qinglan.Tween || {};
/**
 * 四次线性方程（t^4）
 * 
 * @type Object
 */
qinglan.Tween.Quartic = {
	easeIn : function(t, b, c, d) {
		return c * (t /= d) * t * t * t + b;
	},
	easeOut : function(t, b, c, d) {
		return -c * ((t = t / d - 1) * t * t * t - 1) + b;
	},
	easeInOut : function(t, b, c, d) {
		if ((t /= d / 2) < 1)
			return c / 2 * t * t * t * t + b;
		return -c / 2 * ((t -= 2) * t * t * t - 2) + b;
	}
};
/**
 * 五次线性方程（t^4）
 * 
 * @type Object
 */
qinglan.Tween.Quintic = {
	easeIn : function(t, b, c, d) {
		return c * (t /= d) * t * t * t * t + b;
	},
	easeOut : function(t, b, c, d) {
		return c * ((t = t / d - 1) * t * t * t * t + 1) + b;
	},
	easeInOut : function(t, b, c, d) {
		if ((t /= d / 2) < 1)
			return c / 2 * t * t * t * t * t + b;
		return c / 2 * ((t -= 2) * t * t * t * t + 2) + b;
	}
};
/**
 * 一次正弦方程（ sin(t) ）
 * 
 * @type Object
 */
qinglan.Tween.Sinusoidal = {
	easeIn : function(t, b, c, d) {
		return -c * Math.cos(t / d * (Math.PI / 2)) + c + b;
	},
	easeOut : function(t, b, c, d) {
		return c * Math.sin(t / d * (Math.PI / 2)) + b;
	},
	easeInOut : function(t, b, c, d) {
		return -c / 2 * (Math.cos(Math.PI * t / d) - 1) + b;
	}
};
/**
 * 指数曲线方程（ 2 ^ t ）
 * 
 * @type Object
 */
qinglan.Tween.Exponential = {
	easeIn : function(t, b, c, d) {
		return (t == 0) ? b : c * Math.pow(2, 10 * (t / d - 1)) + b;
	},
	easeOut : function(t, b, c, d) {
		return (t == d) ? b + c : c * (-Math.pow(2, -10 * t / d) + 1) + b;
	},
	easeInOut : function(t, b, c, d) {
		if (t == 0)
			return b;
		if (t == d)
			return b + c;
		if ((t /= d / 2) < 1)
			return c / 2 * Math.pow(2, 10 * (t - 1)) + b;
		return c / 2 * (-Math.pow(2, -10 * --t) + 2) + b;
	}
};
/**
 * 园方程（ sqrt(1-t^2) ）
 * 
 * @type Object
 */
qinglan.Tween.Circular = {
	easeIn : function(t, b, c, d) {
		return -c * (Math.sqrt(1 - (t /= d) * t) - 1) + b;
	},
	easeOut : function(t, b, c, d) {
		return c * Math.sqrt(1 - (t = t / d - 1) * t) + b;
	},
	easeInOut : function(t, b, c, d) {
		if ((t /= d / 2) < 1)
			return -c / 2 * (Math.sqrt(1 - t * t) - 1) + b;
		return c / 2 * (Math.sqrt(1 - (t -= 2) * t) + 1) + b;
	}
};
/**
 * 指数衰减的正弦曲线
 * 
 * @type Object
 */
qinglan.Tween.Elastic = {
	easeIn : function(t, b, c, d, a, p) {
		if (t == 0)
			return b;
		if ((t /= d) == 1)
			return b + c;
		if (!p)
			p = d * .3;
		if (!a || a < Math.abs(c)) {
			a = c;
			var s = p / 4;
		} else
			var s = p / (2 * Math.PI) * Math.asin(c / a);
		return -(a * Math.pow(2, 10 * (t -= 1)) * Math.sin((t * d - s)
				* (2 * Math.PI) / p))
				+ b;
	},
	easeOut : function(t, b, c, d, a, p) {
		if (t == 0)
			return b;
		if ((t /= d) == 1)
			return b + c;
		if (!p)
			p = d * .3;
		if (!a || a < Math.abs(c)) {
			a = c;
			var s = p / 4;
		} else
			var s = p / (2 * Math.PI) * Math.asin(c / a);
		return (a * Math.pow(2, -10 * t)
				* Math.sin((t * d - s) * (2 * Math.PI) / p) + c + b);
	},
	easeInOut : function(t, b, c, d, a, p) {
		if (t == 0)
			return b;
		if ((t /= d / 2) == 2)
			return b + c;
		if (!p)
			p = d * (.3 * 1.5);
		if (!a || a < Math.abs(c)) {
			a = c;
			var s = p / 4;
		} else
			var s = p / (2 * Math.PI) * Math.asin(c / a);
		if (t < 1)
			return -.5
					* (a * Math.pow(2, 10 * (t -= 1)) * Math.sin((t * d - s)
							* (2 * Math.PI) / p)) + b;
		return a * Math.pow(2, -10 * (t -= 1))
				* Math.sin((t * d - s) * (2 * Math.PI) / p) * .5 + c + b;
	}
};
/**
 * 超过范围的三次方方程
 * 
 * @type Object
 */
qinglan.Tween.Back = {
	easeIn : function(t, b, c, d, s) {
		if (s == undefined)
			s = 1.70158;
		return c * (t /= d) * t * ((s + 1) * t - s) + b;
	},
	easeOut : function(t, b, c, d, s) {
		if (s == undefined)
			s = 1.70158;
		return c * ((t = t / d - 1) * t * ((s + 1) * t + s) + 1) + b;
	},
	easeInOut : function(t, b, c, d, s) {
		if (s == undefined)
			s = 1.70158;
		if ((t /= d / 2) < 1)
			return c / 2 * (t * t * (((s *= (1.525)) + 1) * t - s)) + b;
		return c / 2 * ((t -= 2) * t * (((s *= (1.525)) + 1) * t + s) + 2) + b;
	}
};
/**
 * 指数衰减的反弹方程
 * 
 * @type Object
 */
qinglan.Tween.Bounce = {
	easeIn : function(t, b, c, d) {
		return c - Tween.Bounce.easeOut(d - t, 0, c, d) + b;
	},
	easeOut : function(t, b, c, d) {
		if ((t /= d) < (1 / 2.75)) {
			return c * (7.5625 * t * t) + b;
		} else if (t < (2 / 2.75)) {
			return c * (7.5625 * (t -= (1.5 / 2.75)) * t + .75) + b;
		} else if (t < (2.5 / 2.75)) {
			return c * (7.5625 * (t -= (2.25 / 2.75)) * t + .9375) + b;
		} else {
			return c * (7.5625 * (t -= (2.625 / 2.75)) * t + .984375) + b;
		}
	},
	easeInOut : function(t, b, c, d) {
		if (t < d / 2)
			return Tween.Bounce.easeIn(t * 2, 0, c, d) * .5 + b;
		else
			return Tween.Bounce.easeOut(t * 2 - d, 0, c, d) * .5 + c * .5 + b;
	}
};